This invention generally relates to a device for opening and holding a frame while an element such as a photographic plate or a holographic element, is placed in or removed from the frame.
Optical elements such as holographic recording mediums and matched filters made from those recording mediums, may be held in frames to facilitate moving and positioning the optical elements. For example, by holding a holographic element in a frame, that element may be moved and otherwise handled without requiring any direct contact against the holographic element itself, other than the contact between the holographic element and the frame. Also, the frame may be specifically shaped or constructed to fit in a device or mechanism used to move or to position the frame and holographic element. One frame that may be used to hold an optical element is described in detail in U.S. patent application No. 903,273, now U.S. Pat. No. 4,806,341.
Often photographic materials used to make holographic elements are placed in and removed from a frame either in the dark or in very low levels of light to minimize any undesirable exposure of the photographic materials. This often makes it difficult to open the frame and to place the photographic materials in and to remove those materials from the frame.